Sex hormones, including LH, FSH, testosterone, estradiol, progesterone, 17 alpha OH progesterone are being examined in hypertensive patients treated with spironolactone, to determine if drug-induced changes on these hormones can account for frequently encountered side-effects such as gynecomastia, decreased libido, and impotence. Since prolonged stimulation of plasma renin activity can interfere with diagnostic studies designed to classify hypertensive patients, the effects of spironolactone therapy and its discontinuation on plasma renin activity, aldosterone excretion rate, and blood pressure are also being examined in hypertensive patients. The data are currently incomplete.